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Physician workload and the Canadian Emergency Department Triage and Acuity Scale: the Predictors of Workload in the Emergency Room (POWER) Study

Published online by Cambridge University Press:  21 May 2015

Jonathan F. Dreyer*
Division of Emergency Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ont.
Shelley L. McLeod
Division of Emergency Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ont.
Chris K. Anderson
School of Hotel Administration, Cornell University, New York, NY Richard Ivey School of Business, University of Western Ontario, London, Ont.
Michael W. Carter
Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ont.
Gregory S. Zaric
Richard Ivey School of Business, University of Western Ontario, London, Ont.
Rm. E1-100, Victoria Hospital, 800 Commissioners Rd. E., London ON N6A 5W9;


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The Canadian Emergency Department Triage and Acuity Scale (CTAS) is a 5-level triage tool used to determine the priority by which patients should be treated in Canadian emergency departments (EDs). To determine emergency physician (EP) workload and staffing needs, many hospitals in Ontario use a case-mix formula based solely on patient volume at each triage level. The purpose of our study was to describe the distribution of EP time by activity during a shift in order to estimate the amount of time required by an EP to assess and treat patients in each triage category and to determine the variability in the distribution of CTAS scoring between hospital sites.


Research assistants directly observed EPs for 592 shifts and electronically recorded their activities on a moment-by-moment basis. The duration of all activities associated with a given patient were summed to derive a directly observed estimate of the amount of EP time required to treat the patient.


We observed treatment times for 11 716 patients in 11 hospital-based EDs. The mean time for physicians to treat patients was 73.6 minutes (95% confidence interval [CI] 63.6–83.7) for CTAS level 1, 38.9 minutes (95% CI 36.0–41.8) for CTAS-2, 26.3 minutes (95% CI 25.4–27.2) for CTAS-3, 15.0 minutes (95% CI 14.6–15.4) for CTAS-4 and 10.9 minutes (95% CI 10.1–11.6) for CTAS-5. Physician time related to patient care activities accounted for 84.2% of physicians' ED shifts.


In our study, EPs had very limited downtime. There was significant variability in the distribution of CTAS scores between sites and also marked variation in EP time related to each triage category. This brings into question the appropriateness of using CTAS alone to determine physician staffing levels in EDs.

Original Research • Recherche originale
Copyright © Canadian Association of Emergency Physicians 2009



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